Dissociation Reaction of Benzyl Alcohol and Benzyl Mercaptan on Ge(100) Surface

Group 14 (100) semiconductor surfaces, such as Ge(100) and Si(100), can be functionalized with organic molecules whose aromatic rings can form a channel for charge transport. Applications of such functionalized semiconductor surfaces in molecular electronics require a comprehensive understanding of the adsorption behavior and surface reactions of organic molecules. In this study, the adsorption structures and corresponding reaction mechanisms of benzyl alcohol and benzyl mercaptan on a Ge(100) surface were investigated by using high-resolution photoemission spectroscopy (HRPES) and density functional theory (DFT) calculations. The HRPES spectra revealed that benzyl alcohol and benzyl mercaptan are adsorbed on the Ge(100) surface via a dissociation reaction, while preserving their aromatic ring. DFT calculations indicated that the dissociation of both molecules preferentially proceeds via the on-top dissociative pathway over the intradimer row dissociative pathway based on a comparison of the adsorption energies of the dissociated species and corresponding activation barriers. These findings regarding the adsorption behavior and surface reactions of aromatic-containing organic molecules will contribute to the development of functionalized semiconductor surfaces for various electronic applications.